1. Field of the Invention:
This invention relates to a device promoting economical operation of automotive vehicles with internal combustion engines driven over roads with varying profiles such as, in particular, roads in
open countryside which in most countries still constitute the major portion of the route traveled by these vehicles.
2. Description of the Prior Art
Such devices of the above-noted type, commonly called "econometers," are already in existence in numerous versions and use electronic components to inform drivers of their instantaneous fuel consumption and encourage them, theoretically, to use slower starting speeds leading to a decrease in the instantaneous unit fuel consumption of the automotive vehicle equipped with the econometer.
Users of these econometers generally complain that these devices provide unrealistic measurements and above all, without actually admitting it, that they only teach the vehicle operator to reduce his instantaneous speed by taking his foot off the accelerator, i.e., by reducing the opening of the butterfly valve in the carburator of the engine or the amount of fuel injected.
To teach drivers to obtain the best performance from their vehicles, i.e., to obtain for the average speed chosen as a function of the possible delays in progress and the profile (slopes and turns) of the road over which they are traveling, the least possible fuel consumption without increasing wear on the vehicle and its engine, more sophisticated methods of furnishing data must be provided to the driver.
Such indicators to aid in economical driving have already been proposed for use on heavy road vehicles, accompanied by instruction by an economical driving monitor, but their proper use requires actual instruction and the presence of qualified personnel and cannot be extended to all the private vehicles for all driving conditions.
Among the reasons why the existing econometers provide unrealistic data on consumption despite a relatively high equipment and above all high installation fee, may be cited the fact that it is necessary to measure continuously and accurately the amount of fuel flowing to the engine, but this measurement is taken for a small and most often differential amount in the feed pumps and the injection pumps where part of the flow returns via a bypass to the fuel tank, which makes such measurements difficult and inaccurate.